By now you should have already glanced through the Editor guide. If not, here is the relevant section on creating pages:

Wiki-Syntax Links
Wiki-syntax links are arguably the single most important feature of wikis. Here is how they work. When you are editing a page, if you put a word inside of a set of double curly brackets, it will automatically make that word into a link to a page who's title is that word.

For example:

If you were to type ((Editor guide)).
You would get Editor guide, which is a link to a page on this wiki that is labeled "user guide", in this case that is this page.

If you make a link to a page that doesn't already exist, you can click the question mark that will appear next to that link and it will create that page for you! This is how you create a page From there you can edit it just like any other page. It's that easy.